Adjusting invoice template: manufacturer name and layout

[Dp.]

 Hi,

I am working on pdf/invoice.product-tab.tpl and I have two issues:

1. In my shop, the product name doe not contain the brand. I add it where needed using {Manufacturer::getnamebyid($product.id_manufacturer)} {$product.name}. In the invoice template, however, the product name is included using {$order_detail.product_name}. Where does this variable come from? And how do I add the manufacturer name enxt to it?
2. I would like to remove the tax id column from the product list which works fine by commenting it out. However, the table then is not full width anymore. In classes/pdf/HTMLTemplateInvoice.php I adjusted this code but without any effect:

$layout = array(
            'reference' => array(
                'width' => 15,
            ),
            'product' => array(
                'width' => 48, /* vorher 40 */
            ),
            'quantity' => array(
                'width' => 8,
            ),
            'tax_code' => array(
                'width' => 0, /* vorher 8 */
            ),
            'unit_price_tax_excl' => array(
                'width' => 0,
            ),
            'total_tax_excl' => array(
                'width' => 0,
            ),
        );